New concrete woes found at nuke plant

SEABROOK — A new issue involving concrete degradation at Seabrook Station nuclear power plant was discovered during a recent quarterly inspection of the plant.

Kyle Stucker

SEABROOK — A new issue involving concrete degradation at Seabrook Station nuclear power plant was discovered during a recent quarterly inspection of the plant.

Nuclear Regulatory Commission staff said two "green" findings, or findings of "very low safety significance," and one violation were discovered during the June 30 inspection.

One of the "green" findings relates to newly discovered degradation in the plant's concrete residual heat-removal vaults. The inspectors' report also states NextEra Energy, the plant's owners, didn't "adequately" evaluate this issue.

While the issue, deemed a "performance deficiency," was considered "more than minor because it affected ... the availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences," NRC inspectors said it "did not represent an actual loss of function."

The plant has drawn criticism from the public in recent years due to findings that an alkali-silica reaction within the plant's concrete is causing cracking and degradation.

Those criticisms have come as NextEra seeks a 20-year extension of its license from 2030 to 2050. The NRC has said a decision on that application won't be made until NextEra completes a number of steps to address the degradation.

NRC Public Affairs Officer Neil Sheehan said there is "no evidence at this point" that the cracking found in the residual heat-removal vaults is the "result" of ASR.

He said "further evaluations are being performed."

The other "green" finding relates to the April 1 automatic trip, in which two of the plant's four reactor coolant pumps shut off ahead of schedule during a planned shutdown.

The reactor was at about 15 percent power when that occurred, plant officials have said. Plant and NRC officials have said NextEra took appropriate action to determine and remedy the cause before the end of the planned shutdown.

The violation was of "very low safety significance" and was identified by NextEra, according to the NRC.

The violation stems from the fact that NextEra found that three of the plant's four reactor coolant pump undervoltage trip channels were "inoperable" for 17 months between a calibration in September 2012 and the April 1 shutdown.

The inspectors' report states NextEra wasn't cited for the violation, though, because the components' inoperability didn't affect the function of other "redundant" reactor trips, plant equipment and procedures. The NRC said it also "did not involve a violation of a regulatory requirement."

The NRC said the issue, which they said "may have arisen over time," has since been corrected.

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